/*jslint adsafe: false, bitwise: true, browser: true, cap: false, css: false,
 debug: false, devel: true, eqeqeq: true, es5: false, evil: false,
 forin: false, fragment: false, immed: true, laxbreak: false, newcap: true,
 nomen: false, on: false, onevar: true, passfail: false, plusplus: true,
 regexp: false, rhino: true, safe: false, strict: false, sub: false,
 undef: true, white: false, widget: false, windows: false */
/*global jQuery: false, window: false */
//"use strict";

/*
 * Original code (c) 2010 Nick Galbreath
 * http://code.google.com/p/stringencoders/source/browse/#svn/trunk/javascript
 *
 * jQuery port (c) 2010 Carlo Zottmann
 * http://github.com/carlo/jquery-base64
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/* base64 encode/decode compatible with window.btoa/atob
 *
 * window.atob/btoa is a Firefox extension to convert binary data (the "b")
 * to base64 (ascii, the "a").
 *
 * It is also found in Safari and Chrome.  It is not available in IE.
 *
 * if (!window.btoa) window.btoa = $.base64.encode
 * if (!window.atob) window.atob = $.base64.decode
 *
 * The original spec's for atob/btoa are a bit lacking
 * https://developer.mozilla.org/en/DOM/window.atob
 * https://developer.mozilla.org/en/DOM/window.btoa
 *
 * window.btoa and $.base64.encode takes a string where charCodeAt is [0,255]
 * If any character is not [0,255], then an exception is thrown.
 *
 * window.atob and $.base64.decode take a base64-encoded string
 * If the input length is not a multiple of 4, or contains invalid characters
 *   then an exception is thrown.
 */

jQuery.base64 = ( function ($) {
    /**
     * UTF16和UTF8转换对照表
     * U+00000000 – U+0000007F   0xxxxxxx
     * U+00000080 – U+000007FF   110xxxxx 10xxxxxx
     * U+00000800 – U+0000FFFF   1110xxxx 10xxxxxx 10xxxxxx
     * U+00010000 – U+001FFFFF   11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
     * U+00200000 – U+03FFFFFF   111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
     * U+04000000 – U+7FFFFFFF   1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
     */
    var Base64 = {
        // 转码表
        table      : [
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
            'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
            'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
            'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
            'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
            'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
            'w', 'x', 'y', 'z', '0', '1', '2', '3',
            '4', '5', '6', '7', '8', '9', '+', '/'
        ],
        UTF16ToUTF8: function (str) {
            var res = [], len = str.length;
            for (var i = 0; i < len; i++) {
                var code = str.charCodeAt(i);
                if (code > 0x0000 && code <= 0x007F) {
                    // 单字节，这里并不考虑0x0000，因为它是空字节
                    // U+00000000 – U+0000007F  0xxxxxxx
                    res.push(str.charAt(i));
                } else if (code >= 0x0080 && code <= 0x07FF) {
                    // 双字节
                    // U+00000080 – U+000007FF  110xxxxx 10xxxxxx
                    // 110xxxxx
                    var byte1 = 0xC0 | ((code >> 6) & 0x1F);
                    // 10xxxxxx
                    var byte2 = 0x80 | (code & 0x3F);
                    res.push(
                        String.fromCharCode(byte1),
                        String.fromCharCode(byte2)
                    );
                } else if (code >= 0x0800 && code <= 0xFFFF) {
                    // 三字节
                    // U+00000800 – U+0000FFFF  1110xxxx 10xxxxxx 10xxxxxx
                    // 1110xxxx
                    var byte1 = 0xE0 | ((code >> 12) & 0x0F);
                    // 10xxxxxx
                    var byte2 = 0x80 | ((code >> 6) & 0x3F);
                    // 10xxxxxx
                    var byte3 = 0x80 | (code & 0x3F);
                    res.push(
                        String.fromCharCode(byte1),
                        String.fromCharCode(byte2),
                        String.fromCharCode(byte3)
                    );
                } else if (code >= 0x00010000 && code <= 0x001FFFFF) {
                    // 四字节
                    // U+00010000 – U+001FFFFF  11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
                } else if (code >= 0x00200000 && code <= 0x03FFFFFF) {
                    // 五字节
                    // U+00200000 – U+03FFFFFF  111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
                } else /** if (code >= 0x04000000 && code <= 0x7FFFFFFF)*/ {
                    // 六字节
                    // U+04000000 – U+7FFFFFFF  1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
                }
            }

            return res.join('');
        },
        UTF8ToUTF16: function (str) {
            var res = [], len = str.length;
            var i = 0;
            for (var i = 0; i < len; i++) {
                var code = str.charCodeAt(i);
                // 对第一个字节进行判断
                if (((code >> 7) & 0xFF) == 0x0) {
                    // 单字节
                    // 0xxxxxxx
                    res.push(str.charAt(i));
                } else if (((code >> 5) & 0xFF) == 0x6) {
                    // 双字节
                    // 110xxxxx 10xxxxxx
                    var code2 = str.charCodeAt(++i);
                    var byte1 = (code & 0x1F) << 6;
                    var byte2 = code2 & 0x3F;
                    var utf16 = byte1 | byte2;
                    res.push(Sting.fromCharCode(utf16));
                } else if (((code >> 4) & 0xFF) == 0xE) {
                    // 三字节
                    // 1110xxxx 10xxxxxx 10xxxxxx
                    var code2 = str.charCodeAt(++i);
                    var code3 = str.charCodeAt(++i);
                    var byte1 = (code << 4) | ((code2 >> 2) & 0x0F);
                    var byte2 = ((code2 & 0x03) << 6) | (code3 & 0x3F);
                    utf16 = ((byte1 & 0x00FF) << 8) | byte2
                    res.push(String.fromCharCode(utf16));
                } else if (((code >> 3) & 0xFF) == 0x1E) {
                    // 四字节
                    // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
                } else if (((code >> 2) & 0xFF) == 0x3E) {
                    // 五字节
                    // 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
                } else /** if (((code >> 1) & 0xFF) == 0x7E)*/ {
                    // 六字节
                    // 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
                }
            }

            return res.join('');
        },
        encode     : function (str) {
            if (!str) {
                return '';
            }
            var utf8 = this.UTF16ToUTF8(str); // 转成UTF8
            var i = 0; // 遍历索引
            var len = utf8.length;
            var res = [];
            while (i < len) {
                var c1 = utf8.charCodeAt(i++) & 0xFF;
                res.push(this.table[c1 >> 2]);
                // 需要补2个=
                if (i == len) {
                    res.push(this.table[(c1 & 0x3) << 4]);
                    res.push('==');
                    break;
                }
                var c2 = utf8.charCodeAt(i++);
                // 需要补1个=
                if (i == len) {
                    res.push(this.table[((c1 & 0x3) << 4) | ((c2 >> 4) & 0x0F)]);
                    res.push(this.table[(c2 & 0x0F) << 2]);
                    res.push('=');
                    break;
                }
                var c3 = utf8.charCodeAt(i++);
                res.push(this.table[((c1 & 0x3) << 4) | ((c2 >> 4) & 0x0F)]);
                res.push(this.table[((c2 & 0x0F) << 2) | ((c3 & 0xC0) >> 6)]);
                res.push(this.table[c3 & 0x3F]);
            }

            return res.join('');
        },
        decode     : function (str) {
            if (!str) {
                return '';
            }

            var len = str.length;
            var i = 0;
            var res = [];

            while (i < len) {
                code1 = this.table.indexOf(str.charAt(i++));
                code2 = this.table.indexOf(str.charAt(i++));
                code3 = this.table.indexOf(str.charAt(i++));
                code4 = this.table.indexOf(str.charAt(i++));

                c1 = (code1 << 2) | (code2 >> 4);
                c2 = ((code2 & 0xF) << 4) | (code3 >> 2);
                c3 = ((code3 & 0x3) << 6) | code4;

                res.push(String.fromCharCode(c1));

                if (code3 != 64) {
                    res.push(String.fromCharCode(c2));
                }
                if (code4 != 64) {
                    res.push(String.fromCharCode(c3));
                }

            }

            return this.UTF8ToUTF16(res.join(''));
        }
    };


    return Base64;

}(jQuery) );